[quasarpod]

Hi Everyone,

I'm very much hoping someone with more expertise in Calibre than I can help me solve this problem.
When adding new books I get the following message:

Failed to add the book: The Ringworld Engineers
D:\My Documents\Larry Niven e books\Niven, Larry\The Ringworld Engineers (1807)\The Ringworld Engineers - Niven, Larry.mobi
With error:
Traceback (most recent call last):
File "site-packages\calibre\gui2\add.py", line 377, in add_book
File "site-packages\calibre\db\legacy.py", line 214, in create_book_entry
File "site-packages\calibre\db\cache.py", line 57, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1530, in create_book_entry
File "site-packages\calibre\db\cache.py", line 1252, in set_metadata
File "site-packages\calibre\db\cache.py", line 1079, in update_path
File "site-packages\calibre\db\backend.py", line 1533, in update_path
File "site-packages\calibre\db\tables.py", line 130, in set_path
File "site-packages\calibre\db\backend.py", line 809, in execute
File "c:\cygwin64\home\kovid\sw\build\apsw-3.8.2-r1\src\cursor.c", line 231, in resetcursor
CantOpenError: CantOpenError: unable to open database file

The problem arose when using the latest version 2.72.0, but this example is from version 2.63, I restored my Win 10 Pro back to September to see if that would solve the problem.
The Calibre library is on a Synology NAS but this example was attempting to load a book from a local drive.
Library maintenance has been run but with no effect.

I would be grateful if someone can point me in the right direction.

Many thanks,
Kris